Post-harvest losses caused by storage insect pests remain a major constraint to cowpea production in sub-Saharan Africa, with Callosobruchus maculatus as the most destructive species. This study evaluated the effectiveness of different storage structures in managing bean weevil infestation and reducing grain losses under laboratory conditions at Nnamdi Azikiwe University, Awka, Nigeria. The storage structures assessed were hermetic bag, jute bag, metal bin, and plastic bag. The experiment was arranged in a Completely Randomized Design with three replications, and data were collected at regular intervals. Results showed significant differences (P < 0.05) among storage structures. The hermetic bag recorded the lowest grain damage (0.51–0.68%), weevil population (0.80–0.82), and weight loss (3.56%). In contrast, the plastic bag had the highest grain damage (13.85%), weevil population (4.90), and weight loss (26.95%), while jute bag and metal bins showed intermediate values. The effectiveness of the hermetic bag is attributed to oxygen depletion and carbon dioxide accumulation, which suppress insect survival and reproduction. The study highlights hermetic storage as an effective approach for reducing post-harvest losses.

Keywords: postharvest losses, bean weevil, insect infestation, grain damage, weight loss, oxygen depletion